Color substrate including retroreflective layer and display device including the color substrate

ABSTRACT

A color substrate and a display device including the same. The color substrate includes: a substrate including first and second pixel regions spaced apart from each other, and a light shielding region between the first and second pixel regions; a first color conversion layer over the first pixel region and configured to convert incident light into first color light; a second color conversion layer over the second pixel region and configured to convert the incident light into second color light; and a retroreflective layer over the light shielding region and configured to retroreflect incident light through the first and second color conversion layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/328,930, filed May 24, 2021, which is a continuation of U.S. patentapplication Ser. No. 16/841,372, filed Apr. 6, 2020, now U.S. Pat. No.11,016,330, which is a continuation of U.S. patent application Ser. No.16/258,475, filed Jan. 25, 2019, now U.S. Pat. No. 10,649,269, which isa continuation of U.S. patent application Ser. No. 15/697,282, filedSep. 6, 2017, now U.S. Pat. No. 10,197,844, which claims priority to andthe benefit of Korean Patent Application No. 10-2016-0137707, filed Oct.21, 2016, the entire content of all of which is incorporated herein byreference.

BACKGROUND 1. Field

One or more aspects of example embodiments of the present disclosurerelate to a color substrate including a retroreflective layer and adisplay device including the color substrate.

2. Description of the Related Art

A liquid crystal display device is a widely used display device andincludes a liquid crystal layer including liquid crystal moleculesconfigured to assume different orientations according to an appliedelectric field (e.g., voltage). The liquid crystal display device may beconfigured to display an image by controlling the polarization ofincident light through the liquid crystal layer.

The liquid crystal display device includes red, blue, and green colorfilters to form light of specific colors. However, when white lightemitted by a backlight source passes through a red color filter, a greencolor filter, and/or a blue color filter, the light intensity is reducedby about ⅓ at each of the red, green, and blue color filters, therebyreducing the light efficiency of the device.

A photo-luminescent liquid crystal display (PL-LCD) apparatus has beensuggested to overcome the low light efficiency of LCD displays and toincrease or improve color reproducibility. The PL-LCD apparatus includesa quantum dot-color conversion layer (QD-CCL) instead of the colorfilters used in a general LCD apparatus. The PL-LCD apparatus displays acolor image when short wavelength light, such as ultraviolet (UV) lightor blue light generated from a light source, is irradiated onto a colorconversion layer (CCL) to thereby generate visible light of differentcolors that is subsequently controlled by a liquid crystal layer.

Since the CCL generates light having a different wavelength from lightemitted by the light source, as opposed to transmitting the light sourcethrough a color filter, light emitted by the CCL is irradiated invarious directions. Furthermore, a portion of the light emitted by thelight source may be transmitted without being converted in a CCL.Accordingly, adjacent first and second color lights emitted by adjacentCCLs and/or a third color light emitted by the light source may mix,thereby changing the apparent colors of each. Color reproducibility maybe reduced due to this color mixing.

A black matrix may be positioned between pixel regions to prevent orreduce color mixing. When the black matrix is formed of a reflectivematerial, light emitted by each CCL may be reflected by the black matrixand irradiated onto an adjacent CCL. In this case, color mixing mayincrease. When the black matrix is formed of a light-absorbing material,the light efficiency may be reduced when light emitted by the CCLs isabsorbed by the black matrix.

SUMMARY

One or more aspects of example embodiments of the present disclosureprovide a color substrate configured to improve color reproducibilityand light efficiency in a display device, and a display device includingthe same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented example embodiments.

According to one or more example embodiments of the present disclosure,a color substrate includes a substrate including first and second pixelregions spaced apart from each other, a light shielding region betweenthe first and second pixel regions, a first color conversion layer overthe first pixel region and configured to convert incident light into afirst color light, a second color conversion layer over the second pixelregion and configured to convert the incident light into a second colorlight, a base material layer over the light shielding region, and firstbeads including a first portion exposed from the base material layer.

The first color conversion layer may include first quantum dotsconfigured to emit the first color light upon being excited by theincident light, the first color light having a wavelength longer thanthat of the incident light; and the second color conversion layer mayinclude second quantum dots configured to emit the second color lightupon being excited by the incident light, the second color light havinga wavelength longer than that of the incident light.

The color substrate may further include a retroreflective layerincluding the base material layer and the first beads and configured toretroreflect light incident from the first and second color conversionlayer.

The retroreflective layer may further include second beads dispersed inthe based material layer, the based material layer surrounding an entiresurface of the second beads.

The first beads may be disposed in an upper portion of the base materiallayer.

The first beads may include the first portion projecting from a topsurface of the base material layer and a second portion embedded in thebase material layer.

The first beads may further include a reflective layer surrounding thesecond portion and exposing the first portion.

The color substrate may further include a color filter layer between thesubstrate and the first and second color conversion layers, the colorfilter layer being configured to transmit the first and second colorlights and to reflect or absorb incident light.

The color substrate may further include a color filter layer over thefirst and second color conversion layers, the color filter layer beingconfigured to transmit incident light and to reflect or absorb the firstand second color lights.

The color substrate may further include a color filter layer surroundingthe side surfaces and upper surfaces of the first and second colorconversion layers, the color filter layer being configured toselectively transmit incident light, and a light shielding sidewall overa part of the color filter layer between the first and second colorconversion layers.

The color substrate may further include a light shielding sidewallsurrounding at least some of the side surfaces of the first and secondcolor conversion layers, and a color filter layer over the first andsecond color conversion layers and the light shielding sidewall, thecolor filter layer being configured to selectively transmit the incidentlight.

The color substrate may further include a color filter layer over athird pixel region spaced apart from the first and second pixel regionsof the substrate, the color filter layer being configured to transmitthe incident light.

The color substrate may further include a third color conversion layerover a third pixel region spaced apart from the first and second pixelregions of the substrate, the third color conversion layer beingconfigured to convert the incident light into a third color light.

The base material layer may be between the first and second colorconversion layers in a horizontal direction, and the first portion ofthe first beads may be exposed from top and side surfaces of the basematerial layer.

According to one or more example embodiments, a color substrate includesa substrate having first and second pixel regions spaced apart from eachother, and a light shielding region between the first and second pixelregions, a first color conversion layer over the first pixel region andconfigured to convert incident light into first color light, a secondcolor conversion layer over the second pixel region and configured toconvert the incident light into second color light, and aretroreflective layer over the light shielding region and configured toretroreflect light incident from the first and second color conversionlayer.

The retroreflective layer may include a retroreflective surface havingconcave patterns.

Each of the concave patterns may be a corner cube pattern having threereflective surfaces positioned orthogonally to each other.

According to one or more example embodiments, a display device includesa display unit including first and second pixels, and a color substrateover the display unit and including first and second pixel regionsrespectively overlapping the first and second pixels, wherein the colorsubstrate includes: a substrate including the first and second pixelregions, and a light shielding region between the first and second pixelregions; a first color conversion layer over the first pixel region, thefirst color conversion layer being configured to convert incident lightinto a first color light; a second color conversion layer over thesecond pixel region, the second color conversion layer being configuredto convert the incident light into a second color light; a base materiallayer over the light shielding region; and first beads including a firstportion exposed from the base material layer.

The display device may further include a backlight device configured toirradiate incident light to the color substrate, and a liquid crystallayer between the display unit and the color substrate.

Each of the first and second pixels may include an organic emissionlayer to emit the incident light.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the example embodiments,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view of a color substrate according to an exampleembodiment of the present disclosure;

FIG. 2 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 3 is an enlarged cross-sectional view of a part of a colorsubstrate according to an example embodiment of the present disclosure;

FIG. 4 is a cross-sectional view of a retroreflective layer of a colorsubstrate according to an example embodiment of the present disclosure;

FIG. 5A is an enlarged cross-sectional view of a part of a colorsubstrate according to an example embodiment of the present disclosure;

FIG. 5B is a plan view of a part of the retroreflective layer of FIG. 5Aaccording to an example embodiment of the present disclosure;

FIG. 6A is an enlarged cross-sectional view of first and second colorconversion layers (CCLs) of a color substrate and a light-emitting layeraccording to an example embodiment of the present disclosure;

FIG. 6B is an enlarged cross-sectional view of first and second CCLs ofa color substrate and a light-emitting layer according to an exampleembodiment of the present disclosure;

FIG. 7 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 8 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 9 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 10 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 11 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 12 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 13 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure;

FIG. 14 is a cross-sectional view of a schematic structure of a displaydevice according to an example embodiment of the present disclosure; and

FIG. 15 is a cross-sectional view of a schematic structure of a displaydevice according to an example embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in more detail to example embodiments,examples of which are illustrated in the accompanying drawings, whereinlike reference numerals refer to like elements throughout andduplicative descriptions thereof may not be provided. In this regard,the present example embodiments may have different forms and should notbe construed as being limited to the descriptions set forth herein.Accordingly, the example embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.Expressions such as “at least one of”, “one of”, and “selected from”,when preceding a list of elements, modify the entire list of elementsand do not modify the individual elements of the list.

It will be understood that when a layer, region, or component isreferred to as being “on”, “provided on”, “positioned on”, or “formedon” another layer, region, or component, it can be directly orindirectly formed on the other layer, region, or component. That is, forexample, intervening layers, regions, or components may be present. Thesizes and thicknesses of elements in the drawings may be exaggerated forconvenience of explanation. In other words, since sizes and thicknessesof components in the drawings are arbitrarily illustrated forconvenience of explanation, the following embodiments are not limitedthereto.

It will be understood that when a layer, region, or component isdescribed as being connected to another portion of the embodiment, thelayer, region, or component may be directly connected to the portion ofthe embodiment, or an intervening layer, region, or component may exist.For example, when a layer, region, or component is described as beingconnected to another portion of the embodiment, the layer, region, orcomponent may be directly connected to the portion of the embodiment, ormay be indirectly connected to the portion of the embodiment throughanother layer, region, or component.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another. An expression used in thesingular encompasses the expression of the plural, unless it has aclearly different meaning in the context. In addition, it will beunderstood that when a unit is referred to as “comprising” anotherelement, it may not exclude other elements but may further include otherelements unless specifically indicated otherwise.

FIG. 1 is a plan view of a color substrate according to an exampleembodiment of the present disclosure. FIG. 2 is a cross-sectional viewof the color substrate according to FIG. 1 , and shows a section takenalong line II-II.

Referring to FIGS. 1 and 2 , a color substrate 100 includes a substrate110, a retroreflective layer 130, a first color conversion layer (CCL)140, and a second CCL 150. The substrate 110 includes a first pixelregion (e.g., pixel area) PA1 and a second pixel region PA2 spaced apartfrom each other, and a light shielding region (e.g., blocking area) BApositioned between and around the first and second pixel regions PA1 andPA2. The first CCL 140 is positioned over the first pixel region PA1 andconverts incident light Li into a first color light Lr. The second CCL150 is positioned over the second pixel region PA2 and converts theincident light Li into a second color light Lg. The retroreflectivelayer 130 is positioned over the light shielding region BA andretroreflects incident light through the first and second CCLs 140 and150.

The color substrate 100 may further include a light-emitting layer 160positioned over a third pixel region PA3, which is spaced apart from thefirst and second pixel regions PA1 and PA2. When the incident light Liis incident on the light-emitting layer 160, the light-emitting layer160 may emit a third color light Lb. The light-emitting layer 160 may bea light-transmitting layer transmitting the incident light Li of thethird color (e.g., Lb), or a third CCL converting the incident light Liinto the third color light Lb. When the color substrate 100 receives theincident light Li and emits the first through third color lights Lr, Lg,and Lb, the color substrate 100 may function as a color filter.

The color substrate 100 may further include a planarization layer 190having a flat upper surface over the first and second CCLs 140 and 150and the light-emitting layer 160.

Referring to FIG. 1 , a pixel region PA and the light shielding regionBA are defined in the substrate 110. The pixel region PA may emit light,and is surrounded by the light shielding region BA. The pixel region PAmay be divided into the first through third pixel regions PA1 throughPA3 corresponding to different colors of emitted light. For example, thefirst pixel region PA1 is a region from which the first color light Lris emitted, the second pixel region PA2 is a region from which thesecond color light Lg is emitted, and the third pixel region PA3 is aregion from which the third color light Lb is emitted. FIG. 1 depicts anexample arrangement of each of the first through third pixel regions PA1through PA3, but embodiments of the present disclosure are not limitedthereto. The arrangement of each of the first through third pixelregions PA1 through PA3 may vary according to suitable arrangements ofpixels of a display device.

The first color light Lr may be red light, the second color light Lg maybe green light, and the third color light Lb may be blue light. The redlight may have a peak wavelength of about 580 nm to about 750 nm. Thegreen light may have a peak wavelength of about 495 nm to about 580 nm.The blue light may have a peak wavelength of about 400 nm to about 495nm.

The light shielding region BA, which does not emit light, may bearranged in a mesh shape or pattern around the first through third pixelregions PA1 through PA3. Light may leak from the display device whenlight is emitted through the light shielding region BA.

The substrate 110 is a transparent substrate through which the first andsecond color lights Lr and Lg emitted by the first and second CCLs 140and 150 may be emitted through the first and second pixel regions PA1and PA2. The third color light Lb may be emitted through the third pixelregion PA3 of the substrate 110.

The substrate 110 may be formed of any suitable material, and may be aninsulating material, for example, glass, plastic, and/or crystal. Thesubstrate 110 may be formed of an organic high-molecular material, forexample, such as polycarbonate (PC), polyethylene terephthalate (PET),polyethylene (PE), polypropylene (PP), polysulfone (PSF),polymethylmethacrylate (PMMA), triacetylcellulose (TAC), cyclo-olefinpolymer (COP), cyclo-olefin polymer, and/or cyclo-olefin copolymer(COC). The material for forming the substrate 110 may be selectedaccording to its mechanical strength, thermal stability, transparency,surface smoothness, ease of handling, and/or water repellency.

The retroreflective layer 130 is positioned over the light shieldingregion BA and retroreflects incident light through the first and secondCCLs 140 and 150. As used herein, the terms “retroreflect” and“retroreflection” indicate reflection of incident light from a lightsource back to that light source. Although incident light andretroreflected light are ideally parallel to each other, the terms asused in the current specification may indicate reflection of light in anapproximate direction of the incident light.

According to an example embodiment of the present disclosure, most of(e.g., half or more) of the first color light Lr emitted by the firstCCL 140 and reflected by the retroreflective layer 130 may be incidenton the first CCL 140. Even if a portion of the first color light Lrreflected by the retroreflective layer 130 is incident on the second CCL150, the first color light Lr is included within a range of the presentexample embodiment as long as half or more of the first color light Lris incident on the first CCL 140. Most of (e.g., half or more) of thesecond color light Lg emitted by the second CCL 150 and reflected by theretroreflective layer 130 may be incident on the second CCL 150.

The retroreflective layer 130 will be described below in more detailwith reference to FIGS. 3, 4, 5A, and 5B.

The first CCL 140 is positioned over the first pixel region PA1, and isconfigured to convert the incident light Li into the first color lightLr and emit the first color light Lr toward the substrate 110. The firstCCL 140 may include first quantum dots configured to emit the firstcolor light Lr having a wavelength longer than that of the incidentlight Li upon being excited by the incident light Li.

The second CCL 150 is positioned over the second pixel region PA2, andis configured to convert the incident light Li into the second colorlight Lg and emit the second color light Lg toward the substrate 110.The second CCL 150 may include second quantum dots configured to emitthe second color light Lg having a wavelength longer than that of theincident light Li upon being excited by the incident light Li.

The light-emitting layer 160 is positioned over the third pixel regionPA3 and emits the third color light Lb toward the substrate 110.

According to an example embodiment of the present disclosure, theincident light Li may be blue light. The light-emitting layer 160 may bea light-transmitting layer transmitting the incident light Li.

According to an example embodiment of the present disclosure, theincident light Li may be ultraviolet (UV) light, wherein the UV lighthas a peak wavelength of about 200 nm to about 400 nm. Thelight-emitting layer 160 may be a third light conversion layerconverting the incident light Li to the third color light Lb andemitting the same, and may include third quantum dots emitting the thirdcolor light Lb having a wavelength longer than that of the incidentlight Li upon being excited by the incident light Li.

The planarization layer 190 may be positioned over the substrate 110 tocover the first and second CCLs 140 and 150 and the light-emitting layer160. The planarization layer 190 may be transparent, such that theincident light Li irradiates the first and second CCLs 140 and 150. Theplanarization layer 190 may be formed of a transparent organic material,such as a polyimide resin, an acryl resin, and/or a resist material. Theplanarization layer 190 may be formed using a wet method, such as a slitcoating method and/or a spin coating method, or a dry method, such as achemical vapor deposition method and/or a vacuum deposition method.However, materials and methods of forming the planarization layer 190are not limited thereto.

A barrier wall may be positioned over the retroreflective layer 130. Thebarrier wall may be positioned around the first and second CCLs 140 and150 and the light-emitting layer 160. Each of the first and second CCLs140 and 150 and the light-emitting layer 160 may be formed on theretroreflective layer 130 in a concave space defined by the barrierwalls using an inkjet method. The barrier wall may be formed of amaterial that is able to absorb or reflect the first through third colorlights Lr, Lg, and Lb.

FIG. 3 is an enlarged cross-sectional view of part A in FIG. 2 ,according to an embodiment of the present disclosure.

FIG. 3 illustrates first and second CCLs 140 and 150 respectivelypositioned over the first and second pixel regions PA1 and PA2 as wellas the light shielding region BA, and retroreflective layer 130 apositioned over the light shielding region BA of the substrate 110.

The first CCL 140 includes a first photosensitive polymer 141 in whichfirst quantum dots 142 are dispersed. The second CCL 150 includes asecond photosensitive polymer 151 in which second quantum dots 152 aredispersed.

Each of the first and second CCLs 140 and 150 may include asemiconductor nanocrystal-polymer complex and may be patterned. Apatterned semiconductor nanocrystal-polymer complex may be obtainedusing a photolithographic process after curing the first and second CCLs140 and 150 by coating, i.e., with a semiconductor nanocrystal-polymersolution. However, embodiments of the present disclosure are not limitedthereto. The semiconductor nanocrystal may include quantum dots (e.g.,an isotropic semiconductor nanocrystal) or, e.g., a quantum confinednanostructure.

The first quantum dots 142 may emit the first color light Lr having awavelength longer than that of the incident light Li upon being excitedby the incident light Li. For example, the first quantum dots 142 absorbblue light and may emit red light having a wavelength longer than thatof the blue light. The second quantum dots 152 may emit the second colorlight Lg having a wavelength longer than that of the incident light Liupon being excited by the incident light Li. For example, the secondquantum dots 152 absorb blue light and may emit green light having awavelength longer than that of the blue light. The first and secondphotosensitive polymers 141 and 151 may each be a light-transmittingorganic material such as, e.g., a silicon resin and/or an epoxy resin.

The wavelengths of light emitted by the first and second quantum dots142 and 152 may be controlled by changing their sizes or compositions. Asize (e.g., length or diameter) of the first quantum dots 142 may bedifferent from that of the second quantum dots 152. When a wavelength ofemitted light increases, sizes of quantum dots for sufficiently inducingsurface plasmon resonance tend to increase (e.g., longer wavelengths ofemitted light are correlated with larger quantum dots, and shorterwavelengths are correlated with smaller quantum dots). Accordingly, whena wavelength of the second color light Lg is shorter than that of thefirst color light Lr, the second quantum dots 152 may be smaller thanthe first quantum dots 142.

The first and second quantum dots 142 and 152 may include a II-VI groupsemiconductor-based compound, a III-V group semiconductor-basedcompound, a IV-VI group semiconductor-based compound, a IV groupsemiconductor-based compound, or a combination thereof. The first andsecond quantum dots 142 and 152 may include the same material.

The II-VI group semiconductor-based compound may be at least one of abinary compound selected from a group consisting of CdSe, CdTe, ZnS,ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and a mixture thereof; aternary compound selected from a group consisting of CdSeS, CdSeTe,CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe,CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, anda mixture thereof; and a quaternary compound selected from a groupconsisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe,CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and a mixture thereof.

The III-V group semiconductor-based compound may be at least one of abinary compound selected from a group consisting of GaN, GaP, GaAs,GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and a mixture thereof;a ternary compound selected from a group consisting of GaNP, GaNAs,GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs,InNSb, InPAs, InPSb, GaAlNP, and a mixture thereof; and a quaternarycompound selected from a group consisting of GaAlNAs, GaAlNSb, GaAlPAs,GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs,InAlNSb, InAlPAs, InAlPSb, and a mixture thereof.

The IV-VI group semiconductor-based compound may be at least one of abinary compound selected from a group consisting of SnS, SnSe, SnTe,PbS, PbSe, PbTe, and a mixture thereof; a ternary compound selected froma group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS,SnPbSe, SnPbTe, and a mixture thereof; and a quaternary compoundselected from a group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and amixture thereof.

The IV group semiconductor-based compound may be at least one of anelemental compound selected from a group consisting of Si, Ge and amixture thereof; and a binary compound selected from a group consistingof SiC, SiGe, and a mixture thereof.

Each of the binary compound, the ternary compound, and the quaternarycompound may be included in a particle at a spatially uniformconcentration, or may be included at varying concentration distributionswithin the same particle. For example, the first and second quantum dots142 and 152 may have a core/shell structure in which a firstsemiconductor nanocrystal (e.g., shell) surrounds a second semiconductornanocrystal (e.g., core). A concentration gradient may be formed at theinterface between the core and the shell. In this case, a concentrationof an element in the shell decreases towards the center (e.g., innerportion) of the shell. The first and second quantum dots 142 and 152 mayhave a structure including a semiconductor nanocrystal core and amulti-layered shell surrounding the core. The multi-layered shellstructure may have two or more layers and each layer may have a singlecomposition, or an alloy or concentration gradient.

When the material of the shell has an energy band gap larger than thematerial of the core in the first and second quantum dots 142 and 152,quantum confinement effects may be efficiently exhibited. When amulti-layered shell is formed, the shell farthest from the core (e.g.,the outermost shell) may have an energy band gap greater than the shellclosest to the core (e.g., the innermost shell).

The first and second quantum dots 142 and 152 may have a quantum yieldof about 10% or more, for example, about 30% or more, about 50% or more,about 60% or more, about 70% or more, or about 90% or more. However,embodiments of the present disclosure are not limited thereto.

The first and second quantum dots 142 and 152 may have a relativelynarrow spectrum width to improve color purity or color reproducibilityin a display. According to an example embodiment, the first and secondquantum dots 142 and 152 may have a light emission wavelength peakhaving a full width at half maximum (FWHM) value of about 45 nm or less,for example, about 40 nm or less, or about 30 nm or less.

Each of the first and second quantum dots 142 and 152 may have aparticle size of about 1 nm to about 100 nm (referring to a diameter ofa spherical dot, or a length of the longest part of the dot if the dotis not spherical). For example, each of the first and second quantumdots 142 and 152 may have a particle size of about 1 nm to about 20 nm.When the first and second quantum dots 142 and 152 are formed of thesame material, the second quantum dots 152 may be smaller than (e.g.,have a smaller particle size than) the first quantum dots 142.

In some embodiments, the first and second CCLs 140 and 150 including asemiconductor nanocrystal-polymer complex may include at least one of aquantum rod and a sheet type semiconductor (e.g., a quantum plate)instead of the first and second quantum dots 142 and 152, or may furtherinclude at least one of the quantum rod and the sheet type semiconductorin addition to the first and second quantum dots 142 and 152.

In some embodiments, the first CCL 140 may include a phosphor configuredto convert the incident light Li into the first color light Lr, and thesecond CCL 150 may include a phosphor configured to convert the incidentlight Li into the first color light Lg.

The retroreflective layer 130 a, which is an example embodiment of theretroreflective layer 130 of FIG. 2 , may include an organic materiallayer 131 (e.g., a base material layer) and beads 132. The terms“organic material layer” and “base material layer” may beinterchangeably used herein.

The organic material layer 131 may be formed of an organic material,such as a polyimide resin, an acryl resin, and/or a resist material. Theorganic material layer 131 may be transparent. In some embodiments, theorganic material layer 131 may include a non-transparent inorganicinsulating material such as CrO_(x) and/or MoO_(x), and/or anon-transparent organic material such as a black resin to block thelight shielding region BA from light. A refractive index of the organicmaterial layer 131 may be lower than that of the beads 132. The organicmaterial layer 131 may be formed of an organic material having a lowerrefractive index in such a manner that total reflection of light occursat a boundary between the organic material layer 131 and the beads 132at a large critical angle.

The beads 132 may be spherical as illustrated in FIG. 3 . In someembodiments, the beads 132 may be elliptical. The beads 132 may beformed of general glass (e.g., silica glass) and/or barium titanateglass. The beads 132 formed of glass may have a refractive index ofabout 1.5, and the beads 132 formed of barium titanate glass may have arefractive index of about 1.9.

The retroreflective layer 130 a may be formed by patterning a polymersolution including the beads 132. For example, the retroreflective layer130 a may be coated with the polymer solution and the polymer solutionmay then be cured. When the polymer solution is photosensitive, theretroreflective layer 130 a may be formed through a photolithographicprocess after being coated with the photosensitive polymer solution.

A portion of the organic material layer 131 in the retroreflective layer130 a may be partially removed so that some of the beads 132 in theretroreflective layer 130 a partially project from (e.g., are partiallyexposed at the top-facing surface of) the organic material layer 131, asillustrated in FIG. 3 . For example, some of the beads 132 may bepartially exposed as illustrated in FIG. 3 when etch-back etching and/orisotropic etching is performed on a structure (e.g., organic materiallayer) generated by curing and patterning a polymer solution includingthe beads 132. When the exposed area of the beads 132 is larger, theamount of light retroreflected by the retroreflective layer 130 a mayincrease. The beads 132 may be embedded in the organic material layer131 so that half of the surface area of the beads 132 is exposed and theremaining half of the surface area is within the organic material layer131. Some of the beads 132 may also partially project from the organicmaterial layer 131 (e.g., be exposed) at side surfaces of theretroreflective layer 130 a (e.g., on surfaces perpendicular or at anangle to the top-facing surface).

As illustrated in FIG. 3 , when the first color light Lr emitted by thefirst quantum dots 142 is incident on the beads 132 of theretroreflective layer 130 a, the first color light Lr is reflected bythe boundary between the beads 132 and the organic material layer 131 sothat it travels in the opposite direction toward the first quantum dots142. Furthermore, when the second color light Lg emitted by the secondquantum dots 152 is incident on the beads 132 of the retroreflectivelayer 130 a, the second color light Lg is reflected by the boundarybetween the beads 132 and the organic material layer 131 so that ittravels in the opposite direction toward the second quantum dots 152. Ifthe beads 132 are completely or substantially spherical, the first andsecond color lights Lr and Lg incident on the retroreflective layer 130a are reflected back to the first and second quantum dots 142 and 152from which the first and second color lights Lr and Lg are emitted.

Therefore, the first color light Lr emitted by the first quantum dots142 is reflected by the retroreflective layer 130 a and becomes incidenton the first CCL 140 again. The second color light Lg emitted by thesecond quantum dots 152 may also travel to (e.g., become incident on)the second CCL 150 after being reflected by the retroreflective layer130 a. Therefore, the color conversion efficiencies and lightefficiencies of the first and second CCLs 140 and 150 may increase.

In addition, the retroreflective layer 130 a may prevent or reduce thefirst color light Lr from being incident on the second CCL 150, and/orprevent or reduce the second color light Lg from being incident on thefirst CCL 140 because retroreflection differs from general reflection,for example, with respect to the angle of incidence and angle ofreflection of incident light. Therefore, color mixing in the first andsecond CCLs 140 and 150 may be prevented or reduced, and thus, colorreproducibility may be improved.

Although FIG. 3 illustrates that the beads 132 are spaced apart fromeach, embodiments of the present disclosure are not limited thereto, andthe beads 132 may be concentrated as much as possible. For example, thebeads 132 may directly contact each other. The beads 132 may be arrangedin a honeycomb (e.g., close-packed) pattern when viewed according to aplan view.

Although FIG. 3 illustrates that the beads 132 are uniformly distributedin a section of the retroreflective layer 130 a, embodiments of thepresent disclosure are not limited thereto, and the beads 132 may bedistributed in only an upper surface of the retroreflective layer 130 a.This distribution may be achieved, for example, by stacking an organicmaterial layer including the beads 132 on top of an organic materiallayer formed without including the beads 132. In some embodiments, aretroreflective layer with the beads 132 distributed only in an uppersurface thereof may be formed by coating a polymer solution on theretroreflective layer, removing a solvent from the polymer solution, andcoating and curing the beads 132 on the retroreflective layer.

FIG. 4 is a cross-sectional view of a retroreflective layer of a colorsubstrate according to an example embodiment of the present disclosure.

Referring to FIG. 4 , a retroreflective layer 130 b includes the organicmaterial layer 131, the beads 132, and a reflective layer 133.

The organic material layer 131 may be formed of an organic material,such as a polyimide resin, an acryl resin, and/or a resist material. Insome embodiments, the organic material layer 131 may include anon-transparent inorganic insulating material such as CrO_(x) and/orMoO_(x), and/or a non-transparent organic material such as a black resinto block the light shielding region BA from light. In some embodiments,the organic material layer 131 may be transparent.

The beads 132 may be spherical and/or elliptical as illustrated in FIG.4 and may be formed of a transparent material. Some of the beads 132 maypartially project from (e.g., may be partially exposed at the top-facingsurface of) the organic material layer 131. Some of the beads 132 mayinclude a first portion 132 a exposed and projecting from the organicmaterial layer 131 and a second portion 132 b embedded in the organicmaterial layer 131. The surface area of the first portion 132 a may besubstantially equal to that of the second portion 132 b. The beads 132that partially project from the organic material layer 131 may bereferred to herein as “first beads”, such that the first beads aredisposed in an upper portion of the organic (base) material layer andinclude a first portion 132 a exposed from (e.g., projecting from a topsurface of) the organic material layer and a second portion 132 bembedded in the organic material layer. The beads 132 that do notproject from the organic material layer 131 may be referred to herein as“second beads”, such that the second beads are embedded in the organic(base) material layer, and the organic material layer surrounds theentire surface of the second beads.

In some embodiments, the beads (e.g., the first beads) may furthercomprise a reflective layer. The reflective layer 133 may be positionedbetween the beads 132 and the organic material layer 131, and maysurround the second portion 132 b of the beads 132. For example, thereflective layer may surround the second portion of the first beads, andexpose the first portion of the first beads. The reflective layer 133may retroreflect light incident on the beads 132. The reflective layer133 may be formed of a metal material having a high reflectioncharacteristic (e.g., a highly reflective metal material), for example,silver (Ag).

The beads 132 coated with the reflective layer 133 may be prepared toform the retroreflective layer 130 b. For example, the beads 132 coatedwith the reflective layer 133 may be dispersed in a polymer solution.The polymer solution including the beads 132 coated with the reflectivelayer 133 may be coated on the substrate 110, patterned, and cured tothereby form the organic material layer 131 including the beads 132coated with the reflective layer 133. Most of the beads 132 may beembedded in the organic material layer 131. Some of the beads 132 mayproject from the organic material layer 131, for example, when the uppersurface of the retroreflective layer 130 a is partially removed. Forexample, some of the beads 132 in an upper portion of theretroreflective layer 130 a may be partially exposed when etch-backetching or isotropic etching is performed on the organic material layer131 in an upper surface of the retroreflective layer 130 a. As anotherexample, some of the beads (e.g., first beads) may project (e.g., beexposed) from top and side surfaces of the organic material layer 131 inan upper surface of the retroreflective layer 130 a. The reflectivelayer 133 surrounding the projecting portion of the projected beads 132may be removed at the same time (e.g., simultaneously), or wet etchingmay be further performed to remove the reflective layer 133.

When light is incident on the beads 132 of the retroreflective layer 130a, the light may be reflected by the reflective layer 133 surroundingthe second portion 132 b of the beads 132 to thereby travel in thedirection of the light source from which the light was emitted.

The beads 132 may be concentrated as much as possible (e.g., packed asclosely as possible), and/or may be distributed in only an upper portionof the retroreflective layer 130 b.

FIG. 5A is an enlarged cross-sectional view of part of a color substrateaccording to an example embodiment of the present disclosure. FIG. 5Acorresponds to area A of FIG. 2 . FIG. 5B is a plan view of theretroreflective layer 130 c of FIG. 5A.

FIG. 5A illustrates first and second CCLs 140 and 150 respectivelypositioned over the first and second pixel regions PA1 and PA2 as wellas the light shielding region BA, and a retroreflective layer 130 cpositioned over the light shielding region BA of the substrate 110. Thefirst CCL 140 includes the first photosensitive polymer 141 in which thefirst quantum dots 142 are dispersed. The second CCL 150 includes thesecond photosensitive polymer 151 in which the second quantum dots 152are dispersed. The first CCL 140 and the second CCL 150 may be the sameas described herein with reference to FIG. 3 .

The retroreflective layer 130 c may be formed of an organic materialhaving a retroreflective surface 135 forming concave patterns. Theconcave patterns may be formed by pressing a stamp having convexpatterns on an organic material layer. The concave patterns may have twoor more planes positioned orthogonally to each other. The planes formingconcave patterns may retroreflect incident light (e.g., in a directionopposite the incident direction).

In order for the planes forming concave patterns to retroreflect light,the refractive index of the material surrounding the retroreflectivesurface 135 of the retroreflective layer 130 b(e.g., the first andsecond photosensitive polymers 141 and 151) may be higher than therefractive index of the organic material forming the retroreflectivelayer 130 b.

The concave patterns may include a corner cube pattern 136 p asillustrated in FIG. 5B. The corner cube pattern 136 p is a concavepattern corresponding to a corner of a rectangular parallelepiped. Thecorner cube pattern 136 p has three reflective surfaces 136 a, 136 b,and 136 c positioned orthogonally to each other. Light incident on thethree reflective surfaces 136 a, 136 b, and 136 c is reflected in adirection opposite an incident direction. In some embodiments, the threereflective surfaces 136 a, 136 b, and 136 c may not be orthogonal toeach other.

In some embodiments, the concave patterns may have two reflectivesurfaces positioned orthogonally to each other and extending in the samedirection. In this case, a section of the retroreflective surface 135may have an uneven shape, for example, a saw-tooth shape.

In some embodiments, the retroreflective surface 135 may have a waveshape. In some embodiments, amorphous concave shapes may be formed inthe retroreflective surface 135.

FIG. 6A is an enlarged cross-sectional view of the first and second CCLs140 and 150 of a color substrate and a light-emitting layer according toan example embodiment of the present disclosure.

Referring to FIG. 6A, the first CCL 140 converts blue incident light Libinto the first color light Lr. The first CCL 140 may include the firstphotosensitive polymer 141 in which the first quantum dots 142 and firstscattered particles 143 are dispersed.

The first quantum dots 142 may isotropically emit the first color lightLr having a wavelength longer than blue light upon being excited by theblue incident light Lib. The first photosensitive polymer 141 may be alight-transmitting organic material. The first scattered particles 143may scatter a portion of the blue incident light Lib that is notinitially absorbed by the first quantum dots 142 so that more of thefirst quantum dots 142 are excited. Therefore, the color conversionefficiency of the first CCL 140 may be increased. The first scatteredparticles 143 may be, e.g., titanium oxide (TiO₂), metal particles,and/or the like. The first quantum dots 142 may include a II-VI groupsemiconductor-based compound, a III-V group semiconductor-basedcompound, a IV-VI group semiconductor-based compound, a IV groupsemiconductor-based compound, or a combination thereof.

The second CCL 150 converts the blue incident light Lib into the secondcolor light Lg. The second CCL 150 may include the second photosensitivepolymer 151, in which the second quantum dots 152 and the secondscattered particles 153 are dispersed.

The second quantum dots 152 may isotropically emit the second colorlight Lg having a wavelength longer than blue light upon being excitedby the blue incident light Lib. The second photosensitive polymer 151,which is a light-transmitting organic material, may include the samematerial as the first photosensitive polymer 141. The second scatteredparticles 153 may scatter a portion of the blue incident light Lib thatis not initially absorbed by the second quantum dots 152 so that more ofthe second quantum dots 152 are excited. Therefore, the color conversionefficiency of the second CCL 150 may be increased. The second scatteredparticles 153 may be, e.g., TiO₂, metal particles, and/or the like, andmay include the same material as that of the first scattered particles143. The second quantum dots 152 may include a II-VI groupsemiconductor-based compound, a III-V group semiconductor-basedcompound, a IV-VI group semiconductor-based compound, a IV groupsemiconductor-based compound, or a combination thereof. The first andsecond quantum dots 142 and 152 may be formed of the same material. Inthis case, the sizes of the second quantum dots 152 may be smaller thanthe sizes of the first quantum dots 142.

A light-transmitting layer 160 a, which is an example embodiment of thelight-emitting layer 160 of FIG. 2 , may transmit the blue incidentlight Lib and/or emit the blue incident light Lib in the direction ofthe substrate 110. The light-transmitting layer 160 a may include athird photosensitive polymer 161 in which third scattered particles 163are dispersed. The third photosensitive polymer 161, which is alight-transmitting organic material such as a silicon resin and/or anepoxy resin, may include the same material as the first and secondphotosensitive polymers 141 and 151. The third scattered particles 163may scatter and emit the blue incident light Lib, and may include thesame material as the first and second scattered particles 143 and 153.

FIG. 6B is an enlarged cross-sectional view of the first and second CCLs140 and 150 of a color substrate and a light-emitting layer according toan example embodiment of the present disclosure.

Referring to FIG. 6B, the first CCL 140 converts UV incident light Liuvinto the first color light Lr. The first CCL 140 may include the firstphotosensitive polymer 141 in which the first quantum dots 142 and thefirst scattered particles 143 are dispersed. The first quantum dots 142may isotropically emit the first color light Lr having a wavelengthlonger than that of UV light upon being excited by the UV incident lightLiuv.

The second CCL 150 converts the UV incident light Liuv into the secondcolor light Lg. The second CCL 150 may include the second photosensitivepolymer 151 in which the second quantum dots 152 and the secondscattered particles 153 are dispersed. The second quantum dots 152 mayisotropically emit the second color light Lg having a wavelength longerthan that of UV light upon being excited by the UV incident light Liuv.

A third CCL 160 b, which is another example embodiment of thelight-emitting layer 160 of FIG. 2 , converts the UV incident light Liuvinto the third color light Lb. The third CCL 160 b may include the thirdphotosensitive polymer 161 in which third quantum dots 162 and the thirdscattered particles 163 are dispersed. The third quantum dots 162 mayisotropically emit the third color light Lb having a wavelength longerthan that of UV light upon being excited by the UV incident light Liuv.The third photosensitive polymer 161, which is a light-transmittingorganic material, may include the same material as the first and secondphotosensitive polymers 141 and 151. The third scattered particles 163may scatter the portion of UV incident light Liuv that is not initiallyabsorbed by the third quantum dots 162 so that more of the third quantumdots 162 are excited. Therefore, the color conversion efficiency of thethird CCL 160 b may be increased. The third scattered particles 163 maybe, e.g., TiO₂, metal particles, and/or the like, and may include thesame material as the first and second scattered particles 143 and 153.The third quantum dots 162 may include a II-VI group semiconductor-basedcompound, a III-V group semiconductor-based compound, a IV-VI groupsemiconductor-based compound, a IV group semiconductor-based compound,or a combination thereof. The first through third quantum dots 142, 152,and 162 may be formed of the same material. In this case, the sizes ofthe third quantum dots 162 may be smaller than the sizes of the secondquantum dots 152.

FIG. 7 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 7 , a color substrate 100 a includes the substrate110, a light shielding layer 120, the retroreflective layer 130, thefirst and second CCLs 140 and 150, the light-transmitting layer 160 a, afirst color filter layer 170, a second color filter layer 180, and theplanarization layer 190.

The blue incident light Lib may be incident on the color substrate 100a, and the first through third color lights Lr, Lg, and Lb may beemitted through the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a, respectively. The first and second CCLs140 and 150 and the light-transmitting layer 160 a may be the same asdescribed herein with reference to FIG. 6A.

The substrate 110 is a transparent substrate configured to transmit thefirst through third color lights Lr, Lg, and Lb. The pixel region PAconfigured to emit light and the light shielding region BA not emittinglight are defined in the substrate 110. The pixel region PA may bedivided into the first pixel region PA1 configured to emit the firstcolor light Lr, the second pixel region PA2 configured to emit thesecond color light Lg, and the third pixel region PA3 configured to emitthe third color light Lb. The pixel regions PA1, PA2, and PA3 are eachsurrounded by portions of the light shielding region BA.

The light shielding layer 120 may be positioned over the light shieldingregion BA. The light shielding layer 120 may be formed over the lightshielding region BA as a thin film. The light shielding layer 120 mayprevent or reduce leakage of light from the light shielding region BA.

The light shielding layer 120 may have various colors, including blackand/or white. When the light shielding layer 120 is black, the lightshielding layer 120 may include a black matrix. When the light shieldinglayer 120 is white, the light shielding layer 120 may include an organicinsulating material such as a white resin. The light shielding layer 120may include a non-transparent inorganic insulating material such asCrO_(x) and/or MoO_(x), or a non-transparent organic material such as ablack resin. When the retroreflective layer 130 has light shieldingcharacteristics, the light shielding layer 120 may be omitted.

The retroreflective layer 130 is positioned over the light shieldinglayer 120 and retroreflects incident light through the first and secondCCLs 140 and 150 and the light-transmitting layer 160 a. Theretroreflective layer 130 may be the same as described herein withreference to FIGS. 3, 4, 5A and 5B.

The first color filter layer 170, which is positioned in the first andsecond pixel regions PA1 and PA2, reflects the blue incident light Libto the first and second CCLs 140 and 150 so that the blue incident lightLib is not emitted to the substrate 110. More of the first and secondquantum dots 142 and 152 in the first and second CCLs 140 and 150 may beexcited when the blue incident light Lib is reflected, and the colorconversion efficiencies of the first and second CCLs 140 and 150 may beincreased. Furthermore, color reproducibility may be improved since theblue incident light Lib is prevented or reduced from being emittedthrough the first and second pixel regions PA1 and PA2.

The first color filter layer 170 may be a blue light reflecting filterthat reflects the blue incident light Lib, or may be a blue lightblocking filter that absorbs the blue incident light Lib. The firstcolor filter layer 170 transmits the first and second color lights Lrand Lg.

Although FIG. 7 illustrates an embodiment in which the first colorfilter layer 170 is continuous over the first and second pixel regionsPA1 and PA2, in some embodiments, the first color filter layer 170 maybe individually positioned over each of the first and second pixelregions PA1 and PA2 (e.g., in segments). The first color filter layer170 positioned over the first pixel region PA1 may be a red lighttransmission filter configured to selectively transmit the first colorlight Lr. The red light transmission filter may reflect the blueincident light Lib and the second and third color lights Lg and Lb. Thefirst color filter layer 170 positioned in the second pixel region PA2may be a green light transmission filter configured to selectivelytransmit the second color light Lg. The green light transmission filtermay reflect the blue incident light Lib and the first and third colorlights Lr and Lb.

The second color filter layer 180, which is positioned over the firstand second CCLs 140 and 150 and the light-transmitting layer 160 a, mayselectively transmit the third color light Lb included in the blueincident light Lib and reflect the first and second color lights Lr andLg emitted by the first and second CCLs 140 and 150, and may thus emitthe first and second color lights Lr and Lg in the direction of thesubstrate 110. Since the second color filter layer 180 reflects thefirst and second color lights Lr and Lg traveling away from thesubstrate 110 and thereby emits the first and second color lights Lr andLg toward a direction of the substrate 110, the light efficiency of thesubstrate may be improved.

The second color filter layer 180 may cover side surfaces and uppersurfaces of the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. In some embodiments, the second colorfilter layer 180 may also provide a flat surface when it is thicklystacked on the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. In this case, the planarization layer190 may be omitted.

When the blue incident light Lib includes red light and/or green light,the green light may be transmitted outside through the first pixelregion PA1 without exciting the first quantum dots 142 in the first CCL140, and the red light may be transmitted outside through the secondpixel region PA2 without exciting the second quantum dots 152 in thesecond CCL 150. Color purity and color reproducibility may deterioratewhen green light as well as the first color light Lr are emitted throughthe first pixel region PA1, and red light as well as the second colorlight Lg are emitted through the second pixel region PA2. Color purityand color reproducibility may be improved when the second color filterlayer 180 selectively transmits only the blue light Lb. For example, thesecond color filter layer 180 may be formed by alternately (e.g.,alternatingly) laminating at least two layers having differentrefractive indexes.

The planarization layer 190 may be positioned over the second colorfilter layer 180 to provide a flat surface. In some embodiments, theplanarization layer 190 may be positioned over the first and second CCLs140 and 150 and the light-transmitting layer 160 a, or the second colorfilter layer 180 may be positioned over the planarization layer 190.

FIG. 8 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 8 , a color substrate 100 b includes the substrate110, the light shielding layer 120, the retroreflective layer 130, thefirst and second CCLs 140 and 150, the light-transmitting layer 160 a,the first color filter layer 170, the second color filter layer 180, alight shielding sidewall 125, and the planarization layer 190.

The substrate 110, the light shielding layer 120, the retroreflectivelayer 130, the first and second CCLs 140 and 150, the light-transmittinglayer 160 a, the first and second color filter layers 170 and 180, blueincident light Lib, first through third pixel regions PA1 through PA3,and the planarization layer 190 may be similar to those described hereinwith reference to FIG. 7 , and the differences will be described in moredetail below.

The light shielding sidewall 125 is positioned over a portion of thesecond color filter layer 180 to surround at least some of the sidesurfaces of the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. The light shielding sidewall 125 may bepositioned over the light shielding layer 120 in areas corresponding tothe light shielding region BA. The light shielding sidewall 125 mayappear to be formed in a mesh shape or pattern when the light shieldinglayer 120 is viewed in a plan view.

The light shielding sidewall 125 may be formed of an organic materialconfigured to block or reflect the first through third color lights Lr,Lg, and Lb emitted by the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a, respectively.

The light shielding sidewall 125 may prevent or reduce first color lightLr emitted from a side surface of the first CCL 140 from being incidenton the second CCL 150 and the light-transmitting layer 160 a. The lightshielding sidewall 125 may prevent or reduce second color light Lgemitted from a side surface of the second CCL 150 from being incident onthe first CCL 140 and the light-transmitting layer 160 a. The lightshielding sidewall 125 may prevent or reduce third color light Lbscattered in the light-transmitting layer 160 a and emitted from a sidesurface of the light-transmitting layer 160 a from being incident on thefirst and second CCLs 140 and 150. Therefore, color purity and colorreproducibility may be improved since color mixing is prevented orreduced by the light shielding sidewall 125.

FIG. 9 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 9 , a color substrate 100 c includes the substrate110, the light shielding layer 120, the retroreflective layer 130, thefirst and second CCLs 140 and 150, the light-transmitting layer 160 a,the first color filter layer 170, a second color filter layer 180 a, alight shielding sidewall 126, and the planarization layer 190.

The substrate 110, the light shielding layer 120, the retroreflectivelayer 130, the first and second CCLs 140 and 150, the light-transmittinglayer 160 a, the first color filter layer 170, the blue incident lightLib, the light shielding region BA, the first through third pixelregions PA1 through PA3, and the planarization layer 190 may be similarto those described positioned herein with reference to FIG. 7 , and thedifferences will be described in more detail below.

A light shielding sidewall 126 may surround at least a portion of theside surfaces of the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. The light shielding sidewall 126 may bepositioned over the light shielding layer 120. The light shieldingsidewall 126 may appear to be formed in a mesh shape or pattern when thelight shielding layer 120 is viewed in a plan view.

The light shielding sidewall 126 may be formed of an organic materialconfigured to block or reflect the first through third color lights Lr,Lg, and Lb emitted by the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a, respectively. Color purity and colorreproducibility may be improved since color mixing is prevented orreduced by the light shielding sidewall 126.

The second color filter layer 180 a, which is positioned over the firstand second CCLs 140 and 150 and the light-transmitting layer 160 a, mayselectively transmit the blue incident light Lib, thereby improvingcolor purity and color reproducibility. Light efficiency may be improvedwhen the second color filter layer 180 a reflects the first and secondcolor lights Lr and Lg emitted by the first and second CCLs 140 and 150.

FIG. 10 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 10 , a color substrate 100 d includes the substrate110, the light shielding layer 120, the retroreflective layer 130, thefirst and second CCLs 140 and 150, the light-transmitting layer 160 a,the first color filter layer 170, a second color filter layer 180 b, thelight shielding sidewall 127, and the planarization layer 190.

The substrate 110, the light shielding layer 120, the retroreflectivelayer 130, the first and second CCLs 140 and 150, the light-transmittinglayer 160 a, the first color filter layer 170, the blue incident lightLib, the light shielding region BA, the first through third pixelregions PA1 through PA3, and the planarization layer 190 may be similarto those described herein with reference to FIG. 7 , and the differenceswill be described in more detail below.

The light shielding sidewall 127 may surround at least a portion of theside surfaces of the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. The light shielding sidewall 127 may bepositioned over the light shielding layer 120. The light shieldingsidewall 127 may appear to be formed in a mesh shape or pattern when thelight shielding layer 120 is viewed in a plan view.

The light shielding sidewall 127 may be formed of metal, and may beconfigured to block or reflect the first through third color lights Lr,Lg, and Lb emitted from the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. For example, the light shieldingsidewall 127 may be formed of silver. Color purity and colorreproducibility may be improved since color mixing is prevented orreduced by the light shielding sidewall 127, and light efficiency may beimproved since the light shielding sidewall 127 reflects the firstthrough third color lights Lr, Lg, and Lb traveling in a side direction.

The second color filter layer 180 b is positioned over the first andsecond CCLs 140 and 150, the light-transmitting layer 160 a, and thelight shielding sidewall 127, and may selectively transmit the blueincident light Lib, thereby improving color purity and colorreproducibility. Light efficiency may be improved since the second colorfilter layer 180 b reflects the first and second color lights Lr and Lgemitted by the first and second CCLs 140 and 150.

FIG. 11 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 11 , a color substrate 100 e includes the substrate110, the light shielding layer 120, the retroreflective layer 130, thefirst and second CCLs 140 and 150, the third CCL 160 b, first throughthird sub color filter layers 170 r, 170 g, and 170 b, the second colorfilter layer 180, and the planarization layer 190.

The UV incident light Liuv may be incident on the color substrate 100 e,and each of the first through third CCLs 140, 150, and 160 b may convertthe UV incident light Liuv to the first through third color lights Lr,Lg, and Lb and may emit the first through third color lights Lr, Lg, andLb. The first through third CCLs 140, 150 and 160 b and the lightshielding region BA may be the same as described herein with referenceto FIG. 6B.

The substrate 110, the light shielding layer 120, the retroreflectivelayer 130, the second color filter layer 180, and the planarizationlayer 190 may be similar to those described herein with reference toFIG. 7 , and the differences will be described in more detail below. Thecolor substrate 100 e may include at least one of the light shieldingsidewalls 125, 126, and 127 of FIGS. 8 to 10 .

The first through third sub color filter layers 170 r, 170 g, and 170 bare positioned over the first through third pixel regions PA1 throughPA3, respectively. The first through third sub color filter layers 170r, 170 g, and 170 b respectively reflect the UV incident light Liuv tothe first through third CCLs 140, 150 and 160 b in such a manner thatthe UV incident light Liuv is not emitted to the substrate 110. A largeramount or proportion of the first through third quantum dots 142, 152,and 162 in the first through third CCLs 140, 150, and 160 b may beexcited when the UV incident light Liuv passing through the firstthrough third CCLs 140, 150 and 160 b is reflected by the first throughthird sub color filter layers 170 r, 170 g, and 170 b. The colorconversion efficiency of the UV incident light Liuv may be improved, andthe UV incident light harmful to human body may be prevented or reducedfrom being transmitted outside. The first through third sub color filterlayers 170 r, 170 g, and 170 b may be UV light reflecting filter(s)and/or UV light blocking filter(s).

The first sub color filter layer 170 r positioned over the first pixelregion PA1 may be a red light transmission filter configured toselectively transmit the first color light Lr. The red lighttransmission filter may reflect or absorb the UV incident light Liuv andthe second and third color lights Lg and Lb. The second color filterlayer 170 g positioned over the second pixel region PA2 may be a greenlight transmission filter configured to selectively transmit the secondcolor light Lg. The green light transmission filter may reflect orabsorb the UV incident light Liuv and the first and third color lightsLr and Lb. The third sub color filter layer 170 b positioned over thethird pixel region PA3 may be a blue light transmission filterconfigured to selectively transmit the third color light Lb. The bluelight transmission filter may reflect or absorb the UV incident lightLiuv and the first and second color lights Lr and Lg.

FIG. 12 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 12 , a color substrate 100 f includes the substrate110, a retroreflective layer 130 f, and the first and second CCLs 140and 150. The substrate 110 includes the first and second pixel regionsPA1 and PA2 spaced apart from each other, and the light shielding regionBA positioned between the first and second pixel regions PA1 and PA2.The first CCL 140 is positioned over the first pixel region PA1 andconverts the incident light Li into the first color light Lr. The secondCCL 150 is positioned over the second pixel region PA2 and converts theincident light Li into the second color light Lg. The retroreflectivelayer 130 f is positioned over the light shielding region BA andretroreflects incident light through the first and second CCLs 140 and150.

The color substrate 100 f may further include the light-emitting layer160 positioned over the third pixel region PA3, which is spaced apartfrom the first and second pixel regions PA1 and PA2. The light-emittinglayer 160 may interact with the incident light Li, and emit the thirdcolor light Lb. The light-emitting layer 160 may be a light-transmittinglayer transmitting the incident light Li of the third color, or a thirdCCL converting the incident light Li into the third color light Lb.Since the color substrate 100 f receives the incident light Li and emitsthe first through third color lights Lr, Lg, and Lb, the color substrate100 f may function as a color filter.

The color substrate 100 f may further include the planarization layer190 having a flat upper surface over the first and second CCLs 140 and150 and the light-emitting layer 160.

The pixel region PA and the light shielding region BA are defined in thesubstrate 110. The pixel region PA configured to emit light issurrounded by the light shielding region BA. The pixel region PA may bedivided into the first through third pixel regions PA1 through PA3according to a color of emitted light. The light shielding region BAthat does not emit light may be arranged in a mesh shape or patternbetween the first through third pixel regions PA1 through PA3. Thesubstrate 110 is a transparent substrate from which the first throughthird color lights Lr, Lg, and Lb are emitted through the first throughthird pixel regions PA1 through PA3, respectively.

The retroreflective layer 130 f is positioned over the light shieldingregion BA and retroreflects incident light through the first and secondCCLs 140 and 150. As used herein, the terms “retroreflect” and“retroreflection” indicate reflection of incident light from a lightsource back to that light source. Although incident light andretroreflected light are ideally parallel to each other, the terms asused in the current specification may indicate reflection of light in anapproximate direction of the incident light. The retroreflective layer130 f, which is positioned between the first and second CCLs 140 and 150and the light-emitting layer 160 when viewed from a horizontal directionof the substrate 110, may function as a barrier wall between the firstand second CCLs 140 and 150 and the light-emitting layer 160. A heightof an upper surface of the retroreflective layer 130 f may besubstantially the same as that of an upper surface of the first andsecond CCLs 140 and 150. The retroreflective layer 130 f may bepositioned over the light shielding region BA of the substrate 110, andthe first and second CCLs 140 and 150 and the light-emitting layer 160may be formed in a concave space limited by the retroreflective layer130 f utilizing an inkjet method.

The structure and components of the retroreflective layer 130 f may bethe same as those of the retroreflective layers 130 a and 130 bdescribed above with reference to FIGS. 3 and 4 . When theretroreflective layer 130 f is positioned between the first and secondCCLs 140 and 150, the first color light Lr emitted by the first CCL 140cannot be irradiated onto the second CCL 150, and the second color lightLg emitted by the second CCL 150 cannot be irradiated onto the first CCL140. Therefore, color mixing between the first and second CCLs 140 and150 may be prevented or reduced. Furthermore, a manufacturing processmay be simplified and a manufacturing time may be reduced because thefirst and second CCLs 140 and 150 and the light-emitting layer 160 maybe formed by an inkjet coating method. The retroreflective layer 130 f,which functions as a barrier wall, may prevent, block, or reduce a colorconverting material coated by an inkjet method from flowing to anotherregion other than a fixed location.

The retroreflective layer 130 f may have a sloped surface due to a largethickness thereof. For example, the retroreflective layer 130 f may havea trapezoidal shape in which the horizontal direction width decreaseswith increasing distance from the substrate 110. When the first andsecond CCLs 140 and 150 and the light-emitting layer 160 formed in theconcave space limited by the retroreflective layer 130 f are formedutilizing an inkjet method, the retroreflective layer 130 f may have aninverted trapezoidal shape in which the horizontal direction widthincreases with increasing distance from the substrate 110. The first andsecond CCLs 140 and 150, the light-emitting layer 160, and theplanarization layer 190 may be the same as described herein withreference to FIG. 2 .

FIG. 13 is a cross-sectional view of a color substrate according to anexample embodiment of the present disclosure.

Referring to FIG. 13 , a color substrate 100 g includes the substrate110, the light shielding layer 120, a retroreflective layer 130 g, thefirst and second CCLs 140 and 150, the light-transmitting layer 160 a,the first and second color filter layers 170 and 180, and theplanarization layer 190.

The blue incident light Li may be incident on the color substrate 100 g,and the first through third color lights Lr, Lg and Lb may be emittedthrough the first and second CCLs 140 and 150 and the light-transmittinglayer 160 a. The first and second CCLs 140 and 150 and thelight-transmitting layer 160 a may be the same as described herein withreference to FIG. 7 .

The substrate 110 may be a transparent substrate configured to transmitthe first through third color lights Lr, Lg, and Lb. The pixel region PAconfigured to emit light and the light shielding region BA notconfigured to emit light are defined in the substrate 110. The pixelregion PA may be divided into the first through third pixel regions PA1through PA3, from which the first through third color lights Lr, Lg, andLb are respectively emitted. The pixel regions PA1, PA2, and PA3 areeach surrounded by portions of the light shielding region BA.

The light shielding layer 120 may be positioned over the light shieldingregion BA. The light shielding layer 120 may be positioned over thelight shielding region BA with a thin film. The light shielding layer120 may prevent or reduce light from being leaked out from the lightshielding region BA.

The retroreflective layer 130 g is positioned over the light shieldinglayer 120 and retroreflects incident light through the first and secondCCLs 140 and 150 and the light-transmitting layer 160 a. Theretroreflective layer 130 g may be positioned over the light shieldinglayer 120 like a barrier wall.

The retroreflective layer 130 g, which is positioned between the firstand second CCLs 140 and 150 and the light-transmitting layer 160 a whenviewed from a horizontal direction of the substrate 110, may function asa barrier wall between the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. The height of an upper surface of theretroreflective layer 130 g may be substantially the same as that of theupper surface of the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. For example, the height of an uppersurface of the retroreflective layer 130 g may be about 80% to about120% of that of the upper surface of the first and second CCLs 140 and150 and the light-transmitting layer 160 a. The retroreflective layer130 g may be positioned over the light shielding region BA of thesubstrate 110, and the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a may be formed in a concave space limitedby the retroreflective layer 130 g by an inkjet method. Components ofthe retroreflective layer 130 g may be the same as those of theretroreflective layers 130 a and 130 b described above with reference toFIGS. 3 and 4 .

The first color filter layer 170, which is positioned over the first andsecond pixel regions PA1 and PA2, reflects the blue incident light Libto the first and second CCLs 140 and 150 such that the blue incidentlight Lib is not incident on the substrate 110. More of the first andsecond quantum dots 142 and 152 in the first and second CCLs 140 and 150may be excited when the blue incident light Lib is reflected, and thecolor conversion efficiency of the first and second CCLs 140 and 150 maythereby be increased. Furthermore, color reproducibility may be improvedwhen the blue incident light Lib is prevented or reduced from beingemitted through the first and second pixel regions PA1 and PA2.

The first color filter layer 170 may be divided into a part over thefirst pixel region PA1 and a part over the second pixel region PA2 bythe retroreflective layer 130 g. The first color filter layer 170positioned over the first pixel region PA1 may be a red lighttransmission filter configured to selectively transmit the first colorlight Lr. The red light transmission filter may reflect the blueincident light Lib and the second and third color lights Lg and Lb. Thefirst color filter layer 170 positioned in the second pixel region PA2may be a green light transmission filter configured to selectivelytransmit the second color light Lg. The green light transmission filtermay reflect the blue incident light Lib and the first and third colorlights Lr and Lb.

The second color filter layer 180, which is positioned over theretroreflective layer 130 g, the first and second CCLs 140 and 150, andthe light-transmitting layer 160 a, may selectively transmit the blueincident light Lib and reflect the first and second color lights Lr andLg emitted by the first and second CCLs 140 and 150 in the direction ofthe substrate 110. Since the second color filter layer 180 reflects thefirst and second color lights Lr and Lg traveling away from thesubstrate 110 and thereby emits the first and second color lights Lr andLg toward the direction of the substrate 110, light efficiency may beimproved.

When the blue incident light Lib includes red light or green light, thegreen light may be transmitted outside through the first pixel regionPA1 without exciting the first quantum dots 142 in the first CCL 140,and the red light may be transmitted outside through the second pixelregion PA2 without exciting the second quantum dots 152 in the secondCCL 150. Color purity and color reproducibility may deteriorate becausegreen light as well as the first color light Lr are emitted by the firstpixel region PA1, and red light as well as the second color light Lg areemitted by the second pixel region PA2. Color purity and colorreproducibility may be improved when the second color filter layer 180selectively transmits only the blue incident light Lib. For example, thesecond color filter layer 180 may be formed by alternately (e.g.,alternatingly) laminating at least two layers having differentrefractive indexes.

The planarization layer 190 may be positioned over the second colorfilter layer 180 to provide a flat surface. In some embodiments, theplanarization layer 190 may be positioned over the first and second CCLs140 and 150 and the light-transmitting layer 160 a, or the second colorfilter layer 180 may be positioned over the planarization layer 190.

FIG. 14 is a cross-sectional view of a schematic structure of a displaydevice according to an example embodiment of the present disclosure.

Referring to FIG. 14 , a display device 1000 includes a backlight device300, a liquid crystal display panel 200, and the color substrate 100.Although the color substrate 100 may be, for example, the colorsubstrate 100 of FIG. 2 , the color substrate 100 may be replaced by anyof the color substrates 100 a to 100 e according to the exampleembodiments described above.

The backlight device 300 may provide light to form an image in theliquid crystal display panel 200. The backlight device 300 may include,e.g., a light source configured to emit the third color light Lb. Insome embodiments, the backlight device 300 may include a light sourceconfigured to emit UV light. In this case, the color substrate 100 e ofFIG. 11 may be used instead of the color substrate 100.

The liquid crystal display panel 200 includes a lower substrate 210, apixel circuit unit 220 positioned above the lower substrate 210, a pixelelectrode 230, a liquid crystal layer 240, and a common electrode 250.The pixel circuit unit 220 includes first through third pixels PX1through PX3. Each of the first through third pixels PX1 through PX3controls the respective pixel electrode 230 positioned thereabove.

The color substrate 100 externally emits the first and second colorlights Lr and Lg by partially converting the blue incident light Libthat is emitted by the backlight device 300 and transmitted through theliquid crystal display panel 200, and may partially transmit the thirdcolor light Lb to the outside without changing its color.

The lower substrate 210 may be formed of glass and/or a transparentplastic material. A lower polarizing unit for transmitting only light ofa certain polarization from the light emitted by the backlight device300 may be positioned at a bottom surface of the lower substrate 210.For example, the lower polarizing unit may be a polarizing platetransmitting only light that is linearly polarized in a first direction.

The pixel circuit unit 220 may include a plurality of thin-filmtransistors, and a gate wire and a data wire for respectively applying agate signal and a data signal to each of the plurality of thin-filmtransistors.

The pixel electrode 230 may receive a data voltage by being connected toa source or drain electrode of the thin-film transistor formed at thepixel circuit unit 220.

The common electrode 250 may be formed over the planarization layer 190of the color substrate 100. An upper polarizing unit may be positionedbetween the planarization layer 190 and the common electrode 250. Theupper polarizing unit may be a polarizing plate transmitting lightlinearly polarized in a second direction that is perpendicular to thefirst direction. However, example embodiment of the present disclosureare not limited thereto, and the upper and lower polarizing units mayboth transmit light having the same polarization.

The liquid crystal layer 240 is positioned between the pixel electrode230 and the common electrode 250, and an arrangement of liquid crystalmolecules included in the liquid crystal layer 240 may be adjustedaccording to a voltage applied between the pixel electrode 230 and thecommon electrode 250. In other words, the arrangement of liquid crystalmolecules in the area of the liquid crystal layer 240 between the pixelelectrode 230 and the common electrode 250 may be controlled accordingto the voltage applied between the pixel electrode 230 and the commonelectrode 250, and thus the liquid crystal layer 240 may be toggledbetween a first mode (on) wherein a polarization of the blue incidentlight Lib is changed and a second mode (off) wherein a polarization ofthe blue incident light Lib is not changed. The liquid crystal layer 240may also be adjusted to express intermediate gray scale values utilizingintermediate degrees of polarization of the blue incident light Lib.

The blue incident light Lib controlled by the portion of the liquidcrystal layer 240 above the first pixel PX1 is converted into the firstcolor light Lr through the first CCL 140, and the first color light Lris externally emitted through the substrate 110. The blue incident lightLib controlled by the portion of the liquid crystal layer 240 above thesecond pixel PX2 is converted into the second color light Lg through theCCL 150, and the second color light Lg is externally emitted through thesubstrate 110. The blue incident light Lib controlled by the portion ofthe liquid crystal layer 240 above the third pixel PX3 passes throughthe light-transmitting layer 160 a, and the third color light Lb isexternally emitted through the substrate 110.

The color substrate 100 includes the substrate 110, the retroreflectivelayer 130, the first and second CCLs 140 and 150, the light-transmittinglayer 160 a, and the planarization layer 190. The substrate 110 includesthe first through third pixel regions PA1 through PA3 spaced apart fromeach other, and the light shielding region BA positioned between thefirst through third pixel regions PA1 through PA3. The first CCL 140 ispositioned in the first pixel region PA1 and converts the blue incidentlight Lib into the first color light Lr. The second CCL 150 ispositioned in the second pixel region PA2 and converts the blue incidentlight Lib into the second color light Lg. The light-transmitting layer160 a is positioned in the third pixel region PA3, in which the blueincident light Lib is incident thereon and the third color light Lb isemitted therefrom. The retroreflective layer 130 is positioned over thelight shielding region BA and retroreflects incident light through thefirst and second CCLs 140 and 150 and the light-transmitting layer 160a. The planarization layer 190 having a flat upper surface is positionedover the first and second CCLs 140 and 150 and the light-transmittinglayer 160 a.

The blue incident light Lib emitted by the backlight device 300 passesthrough the liquid crystal display panel 200 and is incident on thecolor substrate 100 after being turned on/off by a pixel region based onimage information. A color image is displayed as the color substrate 100externally emits the first and second color lights Lr and Lg byconverting the color of a portion of the blue incident light Lib passingthrough the liquid crystal display panel 200, and externally emits aportion of the blue incident light Lib without changing its color. Colorpurity and light efficiency are improved due to the retroreflectivelayer 130.

FIG. 15 is a cross-sectional view of a schematic structure of a displaydevice according to an example embodiment of the present disclosure.

Referring to FIG. 15 , a display device 2000 includes an organiclight-emitting display panel 400 and the color substrate 100.

The organic light-emitting display panel 400 include the first throughthird pixels PX1 through PX3, and further includes organiclight-emitting diodes (OLEDs) respectively controlled by the firstthrough third pixels PX1 through PX3. Each of the OLEDs may emit thirdcolor light having a light intensity controlled by each of the firstthrough third pixels PX1 through PX3, for example, the blue incidentlight Lib.

The color substrate 100 may externally emit the first and second colorlights Lr and Lg by converting a portion of the blue incident light Libemitted by the OLEDs, and externally emits a portion of the blueincident light Lib without changing its color.

In some embodiments, the OLEDs may emit UV light. In this case, thecolor substrate 100 e of FIG. 11 may be used instead of the colorsubstrate 100. A substrate 410 may be formed of a material such asglass, metal, and/or an organic material.

A pixel circuit layer 420 including the first through third pixels PX1through PX3 is arranged on the substrate 410. Each of the first throughthird pixels PX1 through PX3 includes a plurality of thin-filmtransistors and a storage capacitor, and the pixel circuit layer 420includes signal lines and a power line to transmit signals and a drivingvoltage applied to the first through third pixels PX1 through PX3 inaddition to the first through third pixels PX1 through PX3.

The thin-film transistors may include a semiconductor layer, a gateelectrode, a source electrode, and a drain electrode. The semiconductorlayer may include amorphous silicon and/or polycrystalline silicon. Thesemiconductor layer may include an oxide semiconductor. Thesemiconductor layer may include a channel region, and source and drainregions that are doped with impurities.

Pixel electrodes 440 are positioned over the pixel circuit layer 420.The pixel electrode 440 may be connected to the source or drainelectrode of the thin-film transistor. The pixel electrode 440 isexposed through an opening of a pixel defining layer 430, and an edge ofthe pixel electrode 440 may be covered by the pixel defining layer 430.

An intermediate layer 450 is positioned over the pixel electrodes 440exposed by the pixel defining layer 430. The intermediate layer 450includes an organic emission layer that may be formed of a low molecularorganic material and/or a high molecular organic material. Theintermediate layer 450 may further selectively include a functionallayer such as a hole transport layer (HTL), a hole injection layer(HIL), an electron transport layer (ETL), and/or an electron injectionlayer (EIL) in addition to the organic emission layer.

A counter electrode 460 is positioned to cover the intermediate layer450 and the pixel defining layer 430.

The counter electrode 460 may be a transparent or semi-transparentelectrode. For example, the counter electrode 460 may be formed of ametal thin-film having a low work function. The counter electrode 460may include a transparent conductive oxide (TCO).

The pixel electrode 440, the intermediate layer 450, and the counterelectrode 460 form the OLED. An encapsulation layer 470 covering thecounter electrode 460 may protect the OLED from external moisture.

The blue incident light Lib emitted by the OLED controlled by the firstpixel PX1 is converted into the first color light Lr through the firstCCL 140, and the first color light Lr is externally emitted through thesubstrate 110. The blue incident light Lib emitted by the OLEDcontrolled by the second pixel PX2 is converted into the second colorlight Lg through the second CCL 150, and the second color light Lg isexternally emitted through the substrate 110. The blue incident lightLib emitted by the OLED controlled by the third pixel PX3 passes throughthe light-transmitting layer 160 a, and the third color light Lb isexternally emitted through the substrate 110.

The color substrate 100 includes the substrate 110, the retroreflectivelayer 130, the first and second CCLs 140 and 150, the light-transmittinglayer 160 a, and the planarization layer 190. The substrate 110 includesthe first through third pixel regions PA1 through PA3 spaced apart fromeach other, and the light shielding region BA positioned between thefirst through third pixel regions PA1 through PA3. The first CCL 140 ispositioned over the first pixel region PA1 and converts the blueincident light Lib into the first color light Lr. The second CCL 150 ispositioned over the second pixel region PA2 and converts the blueincident light Lib into the second color light Lg. Thelight-transmitting layer 160 a is positioned over the third pixel regionPA3, in which the blue incident light Lib is incident thereon and thethird color light Lb is emitted therefrom. The retroreflective layer 130is positioned over the light shielding region BA and retroreflectsincident light through the first and second CCLs 140 and 150 and thelight-transmitting layer 160 a. The planarization layer 190 having aflat upper surface is positioned over the first and second CCLs 140 and150 and the light-transmitting layer 160 a.

The blue incident light Lib emitted by the organic light-emittingdisplay panel 400 is incident on the color substrate 100. A color imageis displayed as the color substrate 100 externally emits the first andsecond color lights Lr and Lg by converting a portion of the blueincident light Lib into light of other colors, and externally emits aportion of the blue incident light Lib without changing its color.

Although FIG. 15 illustrates that the color substrate 100 is positionedover the organic light-emitting display panel 400, in some embodiments,the organic light-emitting display panel 400 may be positioned over thecolor substrate 100 when the organic light-emitting display panel 400 isa bottom-emission type.

It should be understood that the example embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exampleembodiment should typically be considered as being available for othersimilar features or aspects in other example embodiments.

As used herein, expressions such as “at least one of”, “one of”, “atleast one selected from”, and “one selected from”, when preceding a listof elements, modify the entire list of elements and do not modify theindividual elements of the list. Further, the use of “may” whendescribing embodiments of the present disclosure refers to “one or moreembodiments of the present disclosure”.

In addition, as used herein, the terms “use”, “using”, and “used” may beconsidered synonymous with the terms “utilize”, “utilizing”, and“utilized”, respectively.

As used herein, the terms “substantially”, “about”, and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsub-ranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

While one or more example embodiments have been described with referenceto the figures, it will be understood by those of ordinary skill in theart that various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claimsand equivalents thereof.

What is claimed is:
 1. A substrate comprising: a first color conversionlayer configured to convert incident light into first color light; asecond color conversion layer spaced from the first color conversionlayer and configured to convert the incident light into second colorlight; and beads distributed under an interface between the first andsecond color conversion layers to reflect light incident through thefirst color conversion layer and/or light incident through the secondcolor conversion layer back into the first color conversion layer and/orthe second color conversion layer, wherein the first color conversionlayer is configured to convert the reflected light into the first colorlight, and/or the second color conversion layer is configured to convertthe reflected light into the second color light.
 2. The substrate ofclaim 1, wherein: the first color conversion layer comprises firstquantum dots to emit the first color light upon being excited by theincident light, the first color light having a wavelength that is longerthan that of the incident light, and the second color conversion layercomprises second quantum dots to emit the second color light upon beingexcited by the incident light, the second color light having awavelength that is longer than that of the incident light.
 3. Thesubstrate of claim 1, further comprising a reflective layer includingthe beads and configured to reflect the light incident from the firstcolor conversion layer, and/or the light incident from the second colorconversion layer, wherein the reflective layer overlaps the interfacebetween the first and second color conversion layers.
 4. The substrateof claim 1, further comprising a filtering layer over the first andsecond color conversion layers, the filtering layer being configured totransmit the first and second color lights, and reflect and/or absorbthe incident light.
 5. The substrate of claim 1, further comprising alight shielding sidewall between the first and second color conversionlayers.
 6. The substrate of claim 5, further comprising a filteringlayer surrounding side surfaces and bottom surfaces of the first andsecond color conversion layers, the filtering layer being configured toselectively transmit the incident light, wherein a part of the filteringlayer is located between the light shielding sidewall and the first andsecond color conversion layers.
 7. The substrate of claim 5, furthercomprising: a filtering layer under the first and second colorconversion layers and the light shielding sidewall, the filtering layerbeing configured to selectively transmit the incident light.
 8. Adisplay device comprising: a first organic emission layer to emit firstlight; a second organic emission layer to emit second light; a firstcolor conversion layer over the first organic emission layer andconfigured to convert the first light into first color light; a secondcolor conversion layer over the second organic emission layer andconfigured to convert the second light into second color light; and areflective layer overlapping an interface between the first and secondcolor conversion layers to reflect the first light incident through thefirst color conversion layer and/or the second light incident throughthe second color conversion layer back into the first color conversionlayer and/or the second color conversion layer, wherein the first colorconversion layer is configured to convert the reflected first light fromthe reflective layer into the first color light, and/or the second colorconversion layer is configured to convert the reflected second lightfrom the reflective layer into the second color light.
 9. The displaydevice of claim 8, wherein the first light is a third color light, thesecond light is the third color light, and the third color light isdifferent from the first color light and is different from the secondcolor light.
 10. The display device of claim 9, wherein the firstorganic emission layer and the second organic emission layer are partsof an organic emission layer to emit the third color light.
 11. Thedisplay device of claim 9, further comprising: a third organic emissionlayer to emit the third color light; and a filtering layer located overthe third organic emission layer and spaced from the first and secondcolor conversion layers, the filtering layer being configured toselectively transmit the third color light.
 12. The display device ofclaim 11, further comprising: a first color filtering layer over thefirst color conversion layer to selectively transmit the first colorlight; a second color filtering layer over the second color conversionlayer to selectively transmit the second color light; and a third colorfiltering layer over the filtering layer to selectively transmit thethird color light.
 13. The display device of claim 8, wherein the firstlight and the second light have a same main wavelength that is shorterthan those of the first and second color lights.
 14. The display deviceof claim 13, further comprising: a third organic emission layer to emitthird light having a main wavelength that is the same as those of thefirst and second lights; and a filtering layer located over the thirdorganic emission layer and spaced from the first and second colorconversion layers.
 15. The display device of claim 14, furthercomprising: a first color filtering layer over the first colorconversion layer to selectively transmit the first color light; a secondcolor filtering layer over the second color conversion layer toselectively transmit the second color light; and a third color filteringlayer over the filtering layer to selectively transmit third color lightdifferent from the first and second color lights.
 16. A substratecomprising: a first color conversion layer configured to convertincident light into first color light; a second color conversion layerspaced from the first color conversion layer and configured to convertthe incident light into second color light; and beads under the firstand second color conversion layers to reflect light incident through thefirst color conversion layer and/or light incident through the secondcolor conversion layer back into the first color conversion layer and/orthe second color conversion layer, wherein the first color conversionlayer is configured to convert the reflected light into the first colorlight, and/or the second color conversion layer is configured to convertthe reflected light into the second color light.
 17. A display devicecomprising: a first organic emission layer to emit first light; a secondorganic emission layer to emit second light; a first color conversionlayer over the first organic emission layer and configured to convertthe first light into first color light; a second color conversion layerover the second organic emission layer and configured to convert thesecond light into second color light; and a reflective layer over thefirst and second color conversion layers to reflect the first lightincident through the first color conversion layer and/or the secondlight incident through the second color conversion layer back into thefirst color conversion layer and/or the second color conversion layer,wherein the first color conversion layer is configured to convert thereflected first light from the reflective layer into the first colorlight, and/or the second color conversion layer is configured to convertthe reflected second light from the reflective layer into the secondcolor light.